A truck driver's direct field of view is significantly more restricted than that of other vehicles, especially passenger vehicles. The difficulties of seeing through mirrors for a commercial vehicle driver of semi-tractor trailers, delivery straight trucks, buses and personal recreational vehicle motor homes are well known and documented. Federal Motor Vehicle Safety Standard (FMVSS) 571.111 Rearview Mirrors (codified at 49 C.F.R. §571.111), sets standards and requirements for vehicles to improve safety and minimize blind spots for drivers in traffic. A typical flat or planar mirror has limited field of view. A convex or spherical mirror provides an increased field of view but the images in the convex or spherical mirror are distorted and minimized. Thus, estimation of both distance and relative closure speeds of traffic approaching the commercial vehicle from behind or alongside is more difficult.
Many trucks have at least six mirrors; each mirror has a different reflective optical quality. This increases the difficulty for the driver to quickly judge the dynamic traffic environment, which increases driver fatigue and the likelihood of a driver making an error.
These matters are well recognized in the extensive researches performed by the University of Michigan Transportation Research Institute for the Department of Transportation. These studies indicate a need for improvements in mirrors available to trucks and large vehicles to reduce side lane-change accidents by minimizing driver confusion and fatigue. This research includes: (1) Daniel Blower, Truck Mirrors, Field of View and Serious Truck Crashes, UMTRI-2007-25 (available at http://deepblue.lib.umich.edu/bitstream/2027.42/58728/1/99830.pdf); (2) Mathew P. Reed, Daniel Blower, Michael J. Flannagan, Prioritizing Improvements to Truck Driver Vision, UMTRI-2005-31 (available at http://deepblue.lib.umich.edu/bitstream/2027.42/83927/1/102737.pdf); (3) Luoma, J., Flannagan, M. J., and Sivak, M., Effects of Non-Planar Driver Side Mirrors on Lane Change Crashes, UMTRI-2006-26 (available at http://deepblue.lib.umich.edu/bitstream/2027.42/49417/1/UMTRI-2000-26.pdf); (4) Helmers, G., Flannagan M. J., Sivak, M., Owens, D. A., Battle, D., and Sato, T., Response Times Using Flat, Convex and Multi-Radius Mirrors, UMTRI-92-20 (available at: http://deepblue.lib.umich.edu/bitstream/2027.42/64070/1/82649.pdf); (5) Luoma, J. Sivak, M., Flannagan, M. J., Effects of Driver-Side Mirror Types on Lane-Change Accidents, UMTRI-94-34 (available at: http://deepblue.lib.umich.edu/bitstream/2027.42/1107/2/59932.0001.001.pdf); (6) Flannagan, M. J., Sivak, M., Schumann, J. Kojima, S., Traube, E. C., Distance Perception in Driver-Side and Passenger-Side Convex Rearview Mirrors: Objects in Mirror are More Complicated Than They Appear, UMTRI-97-32 (available at: http://deepblue.lib.umich.edu/bitstream/2027.42/49363/1/UMTRI-97-32.pdf); and (7) Sivak, M., Devonshire, J., Flannagan, M. J., Reed, M. P., Mirror Size and Lane-Change Crashes, UMTRI-2008-32 (available at: http://deepblue.lib.umich.edu/bitstream/2027.42/58738/1/100958.pdf), which are hereby incorporated by reference in their entirety.
The prior art contain many shortcomings that are resolved by the present invention. For example, the prior art mirrors have been developed for automobiles, except as noted below, and not the special requirements of trucks and other large vehicles. The prior art mirrors also do not provide a clear and true field of view since the prior art mirrors distort images in size and depth perception resulting in objects appearing further away and smaller than the objects actually are. This is because the prior art mirrors have used progressive multi-radius, spherical designs or a combination of these. The prior art mirrors have not been designed with both different sectional widths and different constant radius combinations in one mirror with a center planar section. All previous automotive designs are wider than taller.
U.S. Pat. No. 3,764,201 issued to Haile teaches a rear vision mirror. This is the only truck mirror prior art that considers adding more field of view for the driver, but does so in a way that includes convex surfaces to the top and bottom along with the outer edge of the planar surface. The adjoining areas of these additional convex surfaces would provide considerable distortion and it does not take advantage of rotating the planar mirror surface outward to provide the most beneficial clear viewing of the adjacent lane for the driver, as does the present invention.
U.S. Pat. No. 4,331,382 issued to Graff teaches a wide-angle mirror for use on automobiles. Graff clearly states that his design is exclusive of buses and trucks larger than pick-ups. It is also claiming a radius of 8 inches±12½% with one outboard mirror surface which has much too small a radius to provide any clarity for what is being seen.
U.S. Pat. No. 8,147,077 issued to Lynam teaches an exterior side view mirror for automobiles. Lynam is presenting the process of providing layers for reflective and protective surfaces, upon preformed backings consisting of polymeric flexible substrate reflective element construction to virtually any combination available for optic quality. Lynam discusses applying this process to curvatures in multi-radius designs erroneously includes spherical and aspherical curvatures which may be on either side in addition to a center planar reflective surface. Lyman teaches designing inboard curvatures of larger radii than outboard curvatures utilizing multi-radius design, which is opposite of the present invention.